Portable computing devices, such as laptop computers, media players, and cellular telephones are becoming increasingly smaller, lighter and more powerful. The ability to fabricate various components of these devices in smaller and smaller sizes, while still maintaining or increasing the power and or operating speed of such devices, has contributed greatly to this trend. Unfortunately, the trend of smaller, lighter and more powerful portable computing devices presents a continuing design challenge in the actual formation of some components for these devices.
One design challenge associated with such portable computing devices is the formation of the enclosures used to house the various internal components of the portable computing devices. This design challenge generally arises from two conflicting design goals—the desirability of making the enclosure lighter and thinner, and the desirability of making the enclosure stronger and more rigid. The lighter enclosures, which typically use thinner plastic structures and fewer fasteners, tend to be more flexible and therefore have a greater propensity to buckle and bow when used, while the stronger and more rigid enclosures, which typically use thicker plastic structures and more fasteners, tend to be thicker and carry more weight. Unfortunately, increased weight may lead to user dissatisfaction, and bowing may damage the internal parts of the portable computing devices.
Furthermore, in most portable computing devices, the enclosures are mechanical assemblies having multiple parts that are screwed, bolted, riveted, or otherwise fastened together at discrete points. For example, the enclosures typically have included an upper casing and a lower casing that are placed on top of one another and fastened together using screws. These techniques typically complicate the housing design and create aesthetic difficulties because of undesirable cracks, seams, gaps or breaks at the mating surfaces and fasteners located along the surfaces of the housing. For example, a mating line surrounding the entire enclosure is produced when using an upper and lower casing. Not only that, but assembly is often a time consuming and cumbersome process, requiring some general technical skill.
Some solutions to these issues have involved the use of an outer housing that is tubular in nature. Such tubular outer housings can be used on, for example the iPod® media player or iPhone® cellular telephone made by Apple Inc., among other suitable portable computing devices or items. One drawback to a common approach of manufacturing such a generally tubular outer housing for a portable computing device is that the process typically involves extruding a heated material and hot-working that material to form the outer housing. Such a hot-working process has a number of inherent problems, including the need to cool the material, the tendency of the material to deform or “wobble” from the desired shape while it is hot, and a resulting relatively rough surface finish that typically must be reworked to result in a smoother finish, among other issues.
While many designs and methods of manufacture for providing outer housings on portable computing devices and other similar items have generally worked well in the past, there is always a desire to provide new and improved designs that result in aesthetically pleasing and functional outer housings for such portable computing devices, as well as improved ways of making such outer housings.